Field of the Invention
The present invention relates to a double-wall pipe having at least a part constructed of an inner pipe defining an inner passage and an outer pipe enveloping the inner pipe so as to define an outer passage together with the inner pipe, and a method of manufacturing a double-wall pipe. The double-wall pipe can be suitably used for a refrigerant cycle device.
Description of the Related Art
A double-wall pipe disclosed in JP-A-2002-318083 includes an inner pipe, and an outer pipe enveloping the inner pipe so as to define a passage together with the inner pipe. The double-wall pipe is capable of performing heat exchange between a first fluid flowing in the inner pipe and a second fluid flowing through the passage between the inner pipe and the outer pipe.
The double-wall pipe is provided in a part thereof with a core held in the outer pipe, and the inner pipe is extended through the core. The part provided with the core of the double-wall pipe is bent by a bending process using a pipe bender to form a bend portion. The bend portion is formed through the bending process, so that lines may not be formed in the bend portion, the bend portion may not be irregularly bent, and the section of the double-wall pipe may not be flattened.
Since the inner pipe and the outer pipe are separated by a space, it is possible that the inner pipe and the outer pipe vibrate, resonate, strike each other, and generate noise when external force is applied to the double-wall pipe.